Rock-drill.



E STAB.

ROCK DRLL.

EPLIOATION HLBD MAY 5, 1911.

' m nl T www Cm ,WTFTT' fi Tw. site ,elle entiteit itiltlnr NIKOLA'US STUB, 0F SCHIFFVJEILER, GER-MANY.

ROCK-DRILL.

Specification of Letters Eatent.

Patenten Mar. 18,91130 Application filed May-5, 1911. Serial No. 625,307.

many, have invented a certain new and useful improved Roelnrill, ot which the tollowing is a specification.

rlhis invention relates to a rock-drill, adapted tor use as brace and jumper, the .'fletaehable chisels of which having crosslike cutting edges which enable an easier advancing of the drill without overheating it in the rock or coal, cutting n round hole therein. in which the chisels do not stick or clamp.

new attacln'nent of the ehisels to the roch-drill adapts the rock-drill tor drilling and jumping.

l'n the accompanying drawing Figure l sliows a side view. Fig. 2 another side view partly in section and Fig. 3 a top view ot the new rock-drill,

The drill has two ehisels u, hitting into a sleeve 7. connecting the chisels with the rod f-, lwo tapering boi-ings at the ends ot the sleeve take up the tapering part of the shrinks ,r/ ot the chisels and the tapering end i1 ot the drill-rod c. Between the two tapering horirgs f the sleeve has a cylindrical boring fr'. lln the shanlts g there are provided recesses toi-ming a tapering hole tor taking up the tapering end (Z ot' tlie liilli'od c. )it opposite lsides otl the tapering end i of the drill-rod e there are projections e tilting into corresponlling recesses o'r the sleeve so that the latter sately coupled with the drilla'odi c.

The cutting edges ot' the chisels have the form or" a cross or the letter X. In consequence ot this the drill can work easier and more freely, because the friction at its sides is diminished and a round hole is cut in the 4 rock in which the chisels do not stick or clamp,

What l do claim and desire to be secured by Letters Patent is:

l. in a tool of the character described, in combination, a sleeve provided with tapering openings extending inwardly Afrom its ends, tool members having shanlrs extending within one of said tapering openings, and a` rod extending within said other tapering opening, said members and said rod being provided with co-acting recessed and projecting portions, whereby they areA interlocled with one another.

2. ln a tool ot the character described, in combination, a sleeve provided. with tapering openings extending inwardly trom its ends, tool members having shanks extending within one of said tapering openings, and a rod extending within said other tapering opening, said members being provided with a tapered recess, and said rod being provided with a tapered projection engaging said recess, whereby the members and the rod will interlock with one another.

In a tool ot' the character described, in combination, a sleeve provided with tapering openings extending inwardly from its ends, tool members having Shanks extend ing within one ot said taperingopenings, and a rod extending within said other tapering opening, said members and said rod 'being interlocked with one another, said sleeve being provided at one end with a recess, and said rod being provided with a projection engaging said recess, whereby said rod is coupled to said sleeve.

in testimony whereof i ailix my signature in presence ot' two witnesses.

Meno. Knnrrmis, OSCAR DnrN En. 

